package 设计模式.strategy;

public abstract class Duck {
    FlyBehavior flyBehavior;

    public Duck(){

    }
    public abstract void display();

    public void quack(){
        System.out.println("鸭子嘎嘎叫");
    }

    public void swim(){
        System.out.println("鸭子会游泳");
    }
    public void fly (){
        if (flyBehavior!=null){
            flyBehavior.fly();
        }
    }
}
